Sc Addition Research Articles

Effect of Zn Content and Sc Addition on Microstructure and Mechanical Properties of Al-Zn-Mg-Cu Alloys

Effect of Zn Content and Sc Addition on Microstructure and Mechanical Properties of Al-Zn-Mg-Cu Alloys

Enhanced Mechanical Properties and Thermal Stability in Additively Manufactured Al-Ni Alloy by Sc Addition

Enhanced Mechanical Properties and Thermal Stability in Additively Manufactured Al-Ni Alloy by Sc Addition

Influence of Sc and Zr additions on microstructure and properties evolution of Al–Zn–Mg alloy

Influence of Sc and Zr additions on microstructure and properties evolution of Al–Zn–Mg alloy

Synergetic Effects of Sc and Zr Additions on Microstructure and Surface Chemical Milling Roughness of 2024-T6 Alloy Sheet

Synergetic Effects of Sc and Zr Additions on Microstructure and Surface Chemical Milling Roughness of 2024-T6 Alloy Sheet

Role of Minor Sc Addition on Precipitation and Mechanical Properties of a New Al-Cu-Li Alloy Under T8 Temper

Role of Minor Sc Addition on Precipitation and Mechanical Properties of a New Al-Cu-Li Alloy Under T8 Temper

Microstructure and Mechanical Properties of Additive Manufactured Inconel 718 Alloy by Oxide Dispersion Strengthening of Sc Addition

Microstructure and Mechanical Properties of Additive Manufactured Inconel 718 Alloy by Oxide Dispersion Strengthening of Sc Addition

Improved intergranular corrosion resistance of Al-Mg-Mn alloys with Sc and Zr additions

Al-5.8Mg-0.4Mn with minor alloying additions of Sc and Zr was investigated via electrochemical testing and nitric acid mass loss testing (NAMLT) in order to reveal the influence of Sc and Zr upon sensitization and intergranular corrosion. The Al-Mg-Mn alloys were also analysed using an electron probe microanalyzer, indicating that β-phase (Al3Mg2) was more likely to precipitate around rectangular or cubic Al6Mn particles. Results reveal that the strength and intergranular corrosion resistance of Al-5.8Mg-0.4Mn was improved by the combined addition of Sc and Zr. The Al3(Sc1-xZrx) dispersoids can lead to an alteration of the relative proportion of low angle grain boundaries, and lower volume fraction of β-phase was observed for Al-5.8Mg-0.4Mn-xSc-yZr relative to the Sc and Zr free alloy.

Precipitation Effects in Cast, Heat-Treated and Cold-Rolled Aluminium AA7075 Alloy with Sc,Zr-Addition

The commercial Al–Zn–Mg–Cu-based alloys (7xxx series) are widely used in metalworking, automotive and aircraft industries as well as in aeronautical applications. The positive effect of the Sc,Zr-addition on mechanical properties of laboratory Al-based alloys is generally known. The microstructure, mechanical and thermal properties of the conventionally cast, heat-treated and cold-rolled Al–Zn–Mg–Cu (–Sc–Zr) alloys during isochronal annealing and natural ageing were studied. Microstructure observation by scanning electron microscopy and transmission electron microscopy proved the Zn,Mg,Cu-containing eutectic phase at grain boundaries. The distinct changes in microhardness curves as well as in a heat flow of the alloys studied are mainly caused by dissolution of the clusters/Guinier-Preston (GP) zones and precipitation of particles from the Al–Zn–Mg–Cu system. An easier diffusion of Zn, Mg and Cu atoms along dislocations in the cold-rolled alloys is responsible for the precipitation of the Zn,Mg,Cu-containing particles at lower temperatures compared to the cast alloys. Microhardness values of the heat-treated alloys increase immediately from the beginning of natural ageing due to the formation of the clusters/GP zones. Addition of Sc and Zr elements results in a higher hardness above ~ 270 °C due to a strengthening by coherent secondary Al3(Sc,Zr) particles with a good thermal stability. Sc,Zr-addition has probably no influence on the evolution of the solute clusters/GP zones.

The microstructure evolution and mechanical properties improvement of the AZ61 alloy by adding Sc

The improvement of mechanical properties and the microstructure evolution through adding Sc to AZ61magnesium alloy were studied. The results indicated that the Mg17Al12 phase in the extruded AZ61 alloy was mainly distributed around the sub-structured and fine deformed grains, resulting in the nonuniform microstructure. The addition of Sc could effectively suppress the band-like precipitation of Mg17Al12 phase and improve the uniformity of microstructure. The grain sizes of the extruded alloys showed a trend of first decreasing and then increasing with the increase of Sc, which was mainly attributed to the secondary phase. The AZ61–0.5Sc alloy exhibited the best mechanical properties, its ultimate tensile strength and yield strength were 14.8MPa and 40.8MPa higher than those of the extruded AZ61 alloy, respectively, which was ascribed to the fine grains and abundant secondary phase in the alloy.

The evolutions of flow stress and microstructure of Al-Mg-Mn-Sc-Zr alloy at elevated temperatures

The Al-Mg-Mn-Sc-Zr alloy is taken as the object and the tensile deformation behaviors at 298 K–673 K are studied in this research. By comparing the evolutions of flow stresses and microstructures, the research finds that the Al-Mg-Mn-Sc-Zr alloy softens apparently when deformed at elevated temperatures. As the temperature increases, the alloy's strength continue to decrease and the elongations continue to increase. The decrease in strength is mainly attributed to the decrease of dislocation density and the change of grain boundaries. In addition, the promotion on the movements of dislocation and softening of grain boundaries by thermal activation also reduces the strength. The increase in elongation is mainly due to the alleviation of stress concentration and the enhancement on the frequency of dislocation slip during the hot deformation process, which promotes the deforming uniformity. Furthermore, the trace addition of Sc and Zr to the Al-Mg alloy forms dispersed nano-sized Al 3 (Sc,Zr) particles in the matrix, which have a strong inhibition on the processes of dynamic recovery and dynamic recrystallization during hot deformation by pinning dislocations and grain boundaries. The Al 3 (Sc,Zr) particles show strong thermal stabilities and the particles' sizes hardly change at 573 K. However, the particles coarsen obviously and the pinning effects on dislocations weakens at 673 K, resulting in a great reduction of flow stress. • The alloy's flow stress decreases significantly as deforming temperatures rising. • Dislocation density decreases with deforming temperature increasing. • High deforming temperature can improve the uniformity of deformation. • Analyzing Al 3 (Sc,Zr) particles' effects on inhibiting dynamic recovery and CDRX.

Effect of La and Sc Co-Addition on the Mechanical Properties and Thermal Conductivity of As-Cast Al-4.8% Cu Alloys

The effects of La and La+Sc addition on mechanical properties and thermal conductivity of Al-4.8Cu alloy were comprehensively studied. The as-cast samples were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and first-principles methods. The results reveal that the grain morphology of Al-4.8Cu alloy changes from dendrite to fine equiaxed grain with La, La+Sc addition. The average grain size of Al-Cu-La (Al-4.8Cu-0.4La) and Al-Cu-La-Sc (Al-4.8Cu-0.4La-0.4Sc) decreased by 37.2% (70.36 μm) and 63.3% (119.64 μm) respectively compared with Al-Cu (Al-4.8Cu). Al-Cu-La has the highest elongation among the three which is 34.4% (2.65%) higher than Al-Cu. Al-Cu-La-Sc has the highest ultimate tensile strength and yield strength which are 55.1% (80.9 MPa) and 65.2% (62.1 MPa) higher than Al-Cu, respectively. The thermal conductivity of Al-Cu-La and Al-Cu-La-Sc is 10.0% (18.797 W·m−1·k−1) and 6.5% (12.178 W·m−1·k−1) higher than Al-Cu alloy respectively. Compared with Al-Cu, Al-Cu-La has less shrinkage and porosity, the presence of Al4La and AlCu3 contribute a lot to the decrease of specific heat capacity and the increase of plasticity and toughness. The porosity of Al-Cu-La-Sc does not significantly decrease compared with Al-Cu-La, the presence of Al3Sc and AlCuSc bring about the increase of specific heat capacity and brittleness.

An as-cast Nb-Si-based alloy with fine-grains and remarkable fracture toughness by minor Sc addition

The effect of Sc addition on the phase composition, microstructure, and room-temperature fracture properties of arc melted Nb-Si-Ti-ZrC-based alloys was systematically investigated. The constituent phases of all alloys are Nbss, γ-(Nb,X)5Si3 and TiC. Sc refines the microstructure, while the grain sizes for the primary γ-(Nb,X)5Si3 and Nbss phases drop from 213 µm and 22.3–23 µm and 5.7 µm, respectively. The content of Nbss and TiC decreases with increasing Sc. The Sc dissolves and then softens Nbss phase. The degree of restraint of Nbss phase decreases with increasing Sc content, therefore causing formation of dimples in the fracture and interface decohesion. Because of the refinement of the primary γ-Nb5Si3 phase, the dimples and interface decohesion created by the low degree of constraint of Nbss phase, the KQ value of Sc3 alloy becomes 16.4 MPa·m1/2. The average grain size of Nbss phase becomes the lowest (5.7 µm), when 0.5 at% Sc is added. The small grain size of Nbss phase deteriorates room-temperature fracture toughness.

Quantifying the effects of Sc and Ag on the microstructure and mechanical properties of Al–Cu alloys

It is well known that the addition of Sc and Ag to Al alloys can promote the nucleation of α-Al grains and θ′-Al2Cu precipitates. In this study, the effects of Sc and Ag on grain size and precipitates, as well as the contribution of grain refinement and precipitation strengthening to yield strength of Al–Cu alloys were quantitatively characterized. The addition of Sc refines the grain size and θ′ precipitate, resulting in the yield strength, ultimate tensile strength and elongation of Al–Cu alloy increasing to 314.2 MPa, 410.6 MPa and 6.31%, respectively. The addition of Ag increases the number density and volume fraction of Ω precipitate, resulting in the contribution of Ω precipitate to the yield strength increasing to 204.8 MPa, and the yield strength, ultimate tensile strength and elongation of Al–Cu alloy reaching 430.0 MPa, 449.9 MPa and 3.60%, respectively. The elastic modulus of AlCuMnMgTiAg alloy is increased to 73 GPa.

Effect of Sc on the Hot Cracking Properties of 7xxx Aluminum Alloy and the Microstructure of Squeeze Castings.

In this paper, the effect of adding the refiner Sc to the high Zn/Mg ratio 7xxx series aluminum alloy melt on the hot tearing performance, microstructure, and mechanical properties of the alloy is studied. The hot tearing performance test (CRC) method is used to evaluate the hot tearing performance of the alloy. The squeeze casting process was used to form solid cylindrical parts to analyze the structure and properties of the alloy. This study shows that the hot cracking sensitivity of the alloy after the addition of the refiner Sc is significantly reduced. The ingot grain size is significantly reduced, and the average grain size is reduced from about 86 μm to about 53 μm. While the mechanical properties are significantly improved, and the tensile strength reduced from 552 MPa is increased to 571 MPa, and the elongation rate is increased from 11% to 14%.

Influence of the Small Sc and Zr Additions on the As-Cast Microstructure of Al–Mg–Si Alloys with Excess Silicon

This research is devoted to the study effects of complex alloying of Al-0.3 wt. % Mg-1 wt. % Si and Al-0.5 wt. % Mg-1.3 wt. % Si alloys by small additions of Sc and Zr on the microstructure in the as-cast condition. The effect of small additions of these elements on the microhardness, electrical conductivity, grain size and phase composition of the indicated alloy systems was studied. The methods of optical and electron microscopy were used for the study. Moreover, the phase composition was calculated using the Thermo-Calc software package. The study showed a strong effect of the chemical composition of investigated alloys on the size of the grains, which, with a certain combination of additives, can decrease several times. Grain refinement occurs both due to supercooling and formation of primary Al3Sc particles in the liquid phase. Alloys based on Al-0.5 wt. % Mg-1.3 wt. % Si are more prone to the formation of this phase since a lower concentration of Sc is required for it to occur. In addition, more silicon interacts with other elements. At the same time, Al-0.3 wt. % Mg-1 wt. % Si requires lower temperature for complete dissolution of Mg2Si, which can contribute to more efficient heat treatment, which includes reducing the number of steps. TEM data show that during ingot cooling (AlSi)3ScZr dispersoid precipitates. This dispersoid could precipitate as coherent and semi-coherent particles with L12 structure as well as needle-shaped particles. The precipitation of coherent and semi-coherent particles during cooling of the ingot indicates that they can be obtained during subsequent multistage heat treatment. In addition, in the Al0.5Mg1.3Si0.3Sc alloy, metastable β″ (Mg5Si6) are precipitated.

Trace Scandium addition on the strength and thermal stability of TiB2 particles reinforced Al-4.5 Cu composites

Strategies employed for developing ultrahigh strength and scalable ductile particles reinforced aluminium-copper matrix composites (AMCs) are highly desirable and grandly challenging. In the present paper, the Scandium (Sc) micro-alloying TiB2 particles reinforced Al-4.5 Cu composites were successfully fabricated by the optimized salt-metal reaction method. The observed microstructures displayed that Sc addition could remarkably ameliorate the dispersion of TiB2 particles, enlarge equiaxed α-Al grain zone and refine the grains on the basis of TiB2 heterogeneous nucleation. In particular, for the 0.4 wt.% Sc microalloyed 5%TiB2/Al-4.5Cu composites, more than a 20 %, 87 %, and 118 % increase in the ultimate tensile strength (UTS), fracture strain elongation (%) and microhardness (HV), respectively were found with respect to the 3 %TiB2/Al-4.5Cu composites at room temperature (298K). The improved mechanical properties of strength-ductility synergy were mainly thanks to the homogeneous distribution of TiB2 particles and modification of Al2Cu phase. Moreover, proper Sc also enhanced the elevated-temperature mechanical properties of the composites with the aid of the accelerated precipitation of θ′ phase and much lower coarsens rate.

Effects of alloying elements on the atomic structure, elastic and thermodynamic properties of L12-Co3(V, Ti) compound

In this work, first-principles calculations were used to study the effects of alloying elements on the atomic structure, elastic property and thermodynamic property of L12 ordered γ′-Co3(V, Ti) at finite temperature. Twenty transition metals (TM), including Sc, Cr, Mn, Fe, Ni, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Hf, Ta, W, Re, Os, Ir and Pt, have been considered as the alloying element at different crystallographic sites. The results show that Mn, Fe, Ru, Os, Rh, Ir, Ni, Pd, and Pt tend to occupy the Co site, while other elements prefer the Ti site of γ′-Co3(V, Ti). In the ground state, all TMs except Cr, Mn, Fe, Y, Tc and Ru could stabilize the γ′-Co3(V, Ti) compound, and the addition of Sc, Fe, Y, Rh, Pd, Ir and Pt can remain the compound a stable phase after involving its competitive phases. The mechanical property of TM-substituted γ'-Co3(V, Ti) was found to be linearly related to both the value of the electron density and the molar volume of compound. However, at finite temperature, only Sc, Y, and Os enhance the thermodynamic stability of the γ'-Co3(V, Ti) with the increasing temperature, which is different from the cases in the ground state.

Effects of small addition of Sc on microstructure and mechanical properties of X2A66 alloy

The effects of Sc addition on the microstructure evolution and mechanical properties of X2A66 alloy were studied by the experimental methods of mechanical property test and microstructure characterization. The results indicate that adding 0.18% Sc element in the X2A66 alloy can effectively refine the grain size, and form the primary phase of AlScZr or AlCuScZr with larger size, and also increases the over firing temperature of the as-cast alloy. Compared with Al3Zr particles, Al3(Sc, Zr) composite particles have better effect on restraining recrystallization, and make the alloy have smaller grain size during the subsequent deformation and heat treatment. However, AlCuSc and AlCuScFe phases can not be completely dissolved in the subsequent heat treatment process, which damages the mechanical properties of the solid solution alloy.

Influence of Sc Addition on Precipitation Behavior and Properties of Al-Cu-Mg Alloy

Influence of Sc Addition on Precipitation Behavior and Properties of Al-Cu-Mg Alloy

Effect of Sc microalloying on microstructure evolution and mechanical properties of extruded Al–Zn–Mg–Cu alloys

The effect of microalloying Sc on the microstructure and mechanical properties of Al–Zn–Mg–Cu alloys was experimentally investigated through X-ray diffraction, optical microscopy, scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy characterizations and tensile tests. The presence of Sc caused the formation of the primary Al3Sc phase and behaved a significant modifying effect on the cast microstructure with an equiaxed microstructure attained in the Sc-bearing alloys rather than the dendrites in Sc-free alloys. In the subsequent thermal extrusion processing, a remarkable grain refinement and retardation of recrystallization occurred, because the nano-sized Al3Sc dispersoids contributed to the pinning effect on the dislocation movement and grain boundary migration in the Sc-bearing alloys. The mechanical properties were significantly improved with the addition of Sc. The superior comprehensive mechanical properties in the Sc-bearing alloys were achieved via the optimal extrusion at 350 °C with the yield strength and ultimate tensile strength of 373.7 ± 3 MPa and 490.3 ± 5 MPa, respectively. The strong strengthening behavior of the Sc addition in the extruded alloys is mainly attributed to the grain refinement and the dispersoid strengthening from the Al3Sc particles. The corresponding contributions to the increase in yield strength derived from the grain refinement and the dispersoid strengthening were estimated, which indicated that the highest particle density attained by extrusion at 350 °C resulted in the excellent mechanical properties of the Sc-bearing alloys.